阅读说明：本技术 输入过压保护系统及方法 (Input overvoltage protection system and method ) 是由 徐冬生 刘建铨 王畅 胡炎申 牛春远 于 2020-12-23 设计创作，主要内容包括：本发明公开了一种输入过压保护系统及方法,系统包括：AC输入单元、整流单元、过压保护单元和VCC供电单元,AC输入单元的输出端接整流单元的输入端,整流单元的输出端接过压保护单元的输入端,过压保护单元的输出端连接VCC供电单元的输入端,过压保护单元用于采样整流单元的输出端电压值,并根据整流单元的输出端电压值控制VCC供电单元的开启和关闭。本方案通过过压保护单元实时采样整流单元输出端的实时电压值,并在实时电压值大于关断电压值时,通过该过压保护单元拉低VCC供电单元的输入端的输入电压,关断VCC供电单元以停止供电,以在电网波动较大的情况下保护电源。(The invention discloses an input overvoltage protection system and a method, wherein the system comprises: the Alternating Current (AC) power supply comprises an AC input unit, a rectifying unit, an overvoltage protection unit and a voltage transformer (VCC) power supply unit, wherein the output end of the AC input unit is connected with the input end of the rectifying unit, the output end of the rectifying unit is connected with the input end of the overvoltage protection unit, the output end of the overvoltage protection unit is connected with the input end of the VCC power supply unit, and the overvoltage protection unit is used for sampling the voltage value of the output end of the rectifying unit and controlling the VCC power supply unit to be turned on or turned off according to. According to the scheme, the overvoltage protection unit is used for sampling the real-time voltage value of the output end of the rectification unit in real time, when the real-time voltage value is larger than the turn-off voltage value, the input voltage of the input end of the VCC power supply unit is pulled down through the overvoltage protection unit, and the VCC power supply unit is turned off to stop power supply, so that the power supply is protected under the condition of large power grid fluctuation.)

1. The utility model provides an input overvoltage protection system, its characterized in that includes AC input unit, rectifier unit, overvoltage protection unit and VCC power supply unit, the output termination of AC input unit the input of rectifier unit, the output termination of rectifier unit the input of overvoltage protection unit, the output of overvoltage protection unit is connected VCC power supply unit's input, overvoltage protection unit is used for the sampling the output voltage value of rectifier unit, and the basis the output voltage value control of rectifier unit VCC power supply unit opens and closes.

2. The input overvoltage protection system according to claim 1, wherein the overvoltage protection unit comprises a voltage-dividing filter module and a switch protection module, an input terminal of the voltage-dividing filter module is connected to an output terminal of the rectifier unit, an output terminal of the voltage-dividing filter module is connected to an input terminal of the overvoltage protection module, an output terminal of the overvoltage protection module is connected to an input terminal of the VCC power supply unit, the voltage-dividing filter module is configured to sample an output terminal voltage value of the rectifier unit, and the switch protection module is configured to control the VCC power supply unit to be turned on and off according to the output terminal voltage value of the rectifier unit.

3. The input overvoltage protection system according to claim 2, wherein the voltage division filtering module comprises a first resistor, a second resistor, a third resistor, a first capacitor and a second capacitor, a first end of the first resistor is connected to the output end of the rectifying unit, a second end of the first resistor is connected to first ends of the second resistor and the first capacitor, a second end of the second resistor is connected to first ends of the third resistor and the second capacitor, and an input end of the switch protection module, and second ends of the third resistor, the first capacitor and the second capacitor are grounded.

4. The input overvoltage protection system according to claim 3, wherein the switch protection module comprises a zener diode, a Mos transistor, a fourth resistor, a fifth resistor, and a third capacitor, wherein a cathode of the zener diode is connected to a first end of the third resistor, an anode of the zener diode is connected to first ends of the third and fourth resistors, and a G pole of the Mos transistor, an S pole of the Mos transistor is connected to a first end of the fifth resistor, a second end of the fifth resistor is connected to an input end of the VCC power supply unit, second ends of the fourth and third resistors, and a D pole of the Mos transistor are grounded.

5. The input overvoltage protection system according to claim 1, wherein the rectification unit is a bridge rectifier circuit.

6. The input overvoltage protection system of claim 1, wherein the VCC unit includes a fast start module and a voltage regulation module, the fast start module is configured to fast start the VCC unit to supply power to the load, and the voltage regulation module is configured to stably supply power to the load.

7. The input overvoltage protection system according to claim 1, further comprising a fuse having a first end connected to the AC input unit and a second end connected to the rectifying unit.

8. An input overvoltage protection method, characterized in that the input overvoltage protection system according to any one of claims 1 to 7 comprises the following steps:

sampling a real-time voltage value at the output end of the rectifying unit in real time;

judging whether the real-time voltage value is larger than a preset turn-off voltage value or not;

if the real-time voltage value is larger than the turn-off voltage value, the input voltage of the input end of the VCC power supply unit is pulled down through the overvoltage protection unit, and the VCC power supply unit is turned off to stop power supply.

9. The input overvoltage protection method according to claim 8, wherein after the step of pulling down the input voltage at the input terminal of the VCC power supply unit by the overvoltage protection unit and turning off the VCC power supply unit to stop supplying power, the method further comprises:

judging whether the real-time voltage value is smaller than a preset recovery voltage value or not;

if the real-time voltage value is smaller than the recovery voltage value, the input voltage of the input end of the VCC power supply unit is pulled up through the overvoltage protection unit, and the VCC power supply unit is started to normally supply power.

10. The input overvoltage protection method according to claim 9, wherein the turn-off voltage value is greater than the recovery voltage value, and a difference between the turn-off voltage value and the recovery voltage value is greater than a specified value.

Technical Field

The invention relates to the field of circuit protection, in particular to an input overvoltage protection system and method.

Background

In the environment near some large-scale equipment or complex power grids, the problem that transient spikes of input voltage are too high (exceeding a specification range) easily occurs, and partial power source components in an electric appliance are damaged due to overstress.

In the design of an LED driving power supply, sometimes in a complex power grid environment, due to the fact that power grid output fluctuation is large, the problem that input voltage is too high (transient spike) exists, the existing LED driving power supply does not have a preset protection function, and partial power supply components of the LED driving power supply are prone to being damaged due to overstress.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an input overvoltage protection system and method.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the invention provides an input overvoltage protection system, which includes an AC input unit, a rectifying unit, an overvoltage protection unit, and a VCC power supply unit, wherein an output terminal of the AC input unit is connected to an input terminal of the rectifying unit, an output terminal of the rectifying unit is connected to an input terminal of the overvoltage protection unit, an output terminal of the overvoltage protection unit is connected to an input terminal of the VCC power supply unit, and the overvoltage protection unit is configured to sample a voltage value at an output terminal of the rectifying unit and control the VCC power supply unit to be turned on and off according to the voltage value at the output terminal of the rectifying unit.

Further, the overvoltage protection unit includes partial pressure filtering module and switch protection module, the input of partial pressure filtering module is connected the output of rectifier unit, the output of partial pressure filtering module is connected the input of overvoltage protection module, the output of overvoltage protection module is connected the input of VCC power supply unit, partial pressure filtering module is used for the sampling the output voltage value of rectifier unit, switch protection module is used for the basis the output voltage value control of rectifier unit VCC power supply unit opens and closes.

Further, the voltage division filtering module comprises a first resistor, a second resistor, a third resistor, a first capacitor and a second capacitor, wherein the first end of the first resistor is connected with the output end of the rectifying unit, the second end of the first resistor is connected with the first ends of the second resistor and the first capacitor, the second end of the second resistor is connected with the first ends of the third resistor and the second capacitor, the input end of the switch protection module is connected with the second ends of the third resistor, the first capacitor and the second capacitor, and the second ends of the third resistor, the first capacitor and the second capacitor are grounded.

Further, the switch protection module comprises a voltage stabilizing diode, a Mos tube, a fourth resistor, a fifth resistor and a third capacitor, wherein the cathode of the voltage stabilizing diode is connected with the first end of the third resistor, the anode of the voltage stabilizing diode is connected with the first ends of the third capacitor and the fourth resistor, the G pole of the Mos tube is connected with the S pole of the fifth resistor, the second end of the fifth resistor is connected with the input end of the VCC power supply unit, the second ends of the fourth resistor and the third capacitor, and the D pole of the Mos tube is grounded.

Further, the rectifying unit is a bridge rectifier circuit.

Further, the VCC unit includes quick start module and voltage stabilizing module, the quick start module is used for quick start the VCC unit supplies power for the load, voltage stabilizing module is used for supplying power for the load stability.

Further, the rectifier circuit further comprises a fuse, wherein a first end of the fuse is connected with the AC input unit, and a second end of the fuse is connected with the rectifier unit.

In a second aspect, the present invention further provides an input overvoltage protection method, based on the input overvoltage protection system, including the following steps:

sampling a real-time voltage value at the output end of the rectifying unit in real time;

judging whether the real-time voltage value is larger than a preset turn-off voltage value or not;

if the real-time voltage value is larger than the turn-off voltage value, the input voltage of the input end of the VCC power supply unit is pulled down through the overvoltage protection unit, and the VCC power supply unit is turned off to stop power supply.

Further, after the step of pulling down the input voltage of the input terminal of the VCC power supply unit and turning off the VCC power supply unit to stop power supply through the overvoltage protection unit, the method further includes:

judging whether the real-time voltage value is smaller than a preset recovery voltage value or not;

if the real-time voltage value is smaller than the recovery voltage value, the input voltage of the input end of the VCC power supply unit is pulled up through the overvoltage protection unit, and the VCC power supply unit is started to normally supply power.

Further, the turn-off voltage value is greater than the recovery voltage value, and a difference between the turn-off voltage value and the recovery voltage value is greater than a specified value.

Compared with the prior art, the invention has the beneficial effects that: the input overvoltage protection system provided by the invention samples the real-time voltage value of the output end of the rectification unit in real time through the overvoltage protection unit, and when the real-time voltage value is larger than the turn-off voltage value, the input voltage of the input end of the VCC power supply unit is pulled down through the overvoltage protection unit, and the VCC power supply unit is turned off to stop supplying power, so as to protect the power supply under the condition of large power grid fluctuation; by sampling the real-time voltage value at the output end of the rectification unit, the timeliness of real-time voltage sampling can be improved, so that the VCC power supply unit can be quickly switched off; by pulling down the input voltage of the input end of the VCC power supply unit, the quick start module and the voltage stabilizing module in the VCC unit can be pulled down simultaneously, and unified control is realized.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented according to the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more apparent, the following detailed description will be given of preferred embodiments.

Drawings

FIG. 1 is a schematic block circuit diagram of an embodiment of an input overvoltage protection system of the present invention;

FIG. 2 is a circuit diagram of an embodiment of an input overvoltage protection system of the present invention;

FIG. 3 is a flow chart of an embodiment of an input over-voltage protection method of the present invention;

fig. 4 is a flowchart of another embodiment of the input overvoltage protection method according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and the detailed description.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be connected or detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above should not be understood to necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.

Referring to fig. 1-2, the present invention provides an input overvoltage protection system, which includes an AC input unit 10, a rectifying unit 20, an overvoltage protection unit 30, and a VCC power supply unit 40, wherein an output terminal of the AC input unit 10 is connected to an input terminal of the rectifying unit 20, an output terminal of the rectifying unit 20 is connected to an input terminal of the overvoltage protection unit 30, an output terminal of the overvoltage protection unit 30 is connected to an input terminal of the VCC power supply unit 40, and the overvoltage protection unit 30 is configured to sample a voltage value of an output terminal of the rectifying unit 20 and control the VCC power supply unit 40 to be turned on or off according to the voltage value of the output terminal of the rectifying unit 20. According to the scheme, the overvoltage protection unit 30 samples the real-time voltage value of the output end of the rectification unit 20 in real time, when the real-time voltage value is larger than the turn-off voltage value, the overvoltage protection unit 30 pulls down the input voltage of the input end of the VCC power supply unit 40, and the VCC power supply unit 40 is turned off to stop power supply, so that a power supply is protected under the condition of large power grid fluctuation; the overvoltage protection unit 30 samples the real-time voltage value at the output end of the rectification unit 20, so that the timeliness of real-time voltage sampling can be improved, and the VCC power supply unit 40 can be quickly switched off; by pulling down the input voltage of the input terminal of the VCC power supply unit 40, the fast start module and the voltage stabilization module in the VCC unit can be pulled down simultaneously, and unified control is realized.

In this embodiment, the overvoltage protection unit 30 includes a voltage division filtering module 31 and a switch protection module 32, an input end of the voltage division filtering module 31 is connected to an output end of the rectifying unit 20, an output end of the voltage division filtering module 31 is connected to an input end of the overvoltage protection module, an output end of the overvoltage protection module is connected to an input end of the VCC power supply unit 40, the voltage division filtering module 31 is configured to sample an output end voltage value of the rectifying unit 20, and the switch protection module 32 is configured to control the VCC power supply unit 40 to be turned on and off according to the output end voltage value of the rectifying unit 20. When the voltage value of the output end of the rectifying unit 20 exceeds the set turn-off voltage value sampled by the voltage division filtering module 31, the input voltage of the input end of the VCC power supply unit 40 is pulled down through the switch protection module 32, and the VCC power supply unit 40 is turned off to stop power supply; and when the voltage dividing and filtering module 31 samples that the voltage value at the output end of the rectifying unit 20 is smaller than the recovery voltage value, the switch protection module 32 pulls up the input voltage at the input end of the VCC power supply unit 40, and the VCC power supply unit 40 is started to normally supply power.

Specifically, the voltage division filtering module 31 includes a first resistor, a second resistor, a third resistor, a first capacitor, and a second capacitor, a first end of the first resistor is connected to the output end of the rectifying unit 20, a second end of the first resistor is connected to the first ends of the second resistor and the first capacitor, a second end of the second resistor is connected to the third resistor and the first end of the second capacitor, and the input terminal of the switch protection module 32, the second terminals of the third resistor, the first capacitor and the second capacitor are grounded, wherein, the first resistor, the second resistor and the third resistor are connected in series in turn to form a voltage dividing loop, when the output voltage of the output end of the rectifying unit 20 changes, the voltage values distributed to the first resistor, the second resistor and the third resistor are correspondingly changed according to the respective resistance values, according to the voltage value change of the third resistor, the real-time monitoring of the output voltage of the output end of the rectifying unit 20 can be realized; the first capacitor and the second capacitor are used for filtering the circuit current.

Referring to fig. 2, in this embodiment, the first resistor is a resistor R7 and a resistor R8 connected in series, the second resistor is a resistor R26, the third resistor is a resistor R27 connected in series with a resistor R37, the first capacitor is a capacitor C23, and the second capacitor is a capacitor C26 connected in parallel with a capacitor C8, where the first resistor, the third resistor, and the second capacitor may also adopt a single resistor or a single capacitor with corresponding parameters.

Referring to fig. 2, the switch protection module 32 includes a zener diode, a Mos transistor, a fourth resistor, a fifth resistor, and a third capacitor, a cathode of the zener diode is connected to a first end of the third resistor, an anode of the zener diode is connected to first ends of the third capacitor and the fourth resistor, and a G pole of the Mos transistor, an S pole of the Mos transistor is connected to a first end of the fifth resistor, a second end of the fifth resistor is connected to an input end of the VCC power supply unit 40, a second end of the fourth resistor and the third capacitor, and a D pole of the Mos transistor is grounded.

The zener diode, Mos tube, fourth resistor, fifth resistor and third capacitor form a switch protection module 32. After the output voltage of the rectifying unit 20 exceeds the turn-off voltage value (that is, the maximum voltage value is allowed), the Mos transistor is turned on when the voltage across the fourth resistor after the output voltage is divided by the zener diode exceeds the turn-on voltage (Vgs) of the Mos transistor, the VCC voltage is reduced to approximately 0V, and the power supply IC is turned off and drives the Mos transistor to stop working, so that the power supply is protected from being damaged; when the input voltage falls below the recovery voltage value, the MOS transistor is turned off (non-conductive), the voltage at the input terminal of the VCC power supply unit 40 is pulled high again, and the power supply IC restarts normal operation.

Referring to fig. 2, in the present embodiment, the zener diode is a zener diode ZD6, the Mos transistor is a Mos transistor Q3, the fourth resistor is a resistor R46, the fifth resistor is a resistor R36, and the third capacitor is a capacitor C15.

As shown in fig. 2, the rectifying unit 20 is a bridge rectifier circuit, and is formed by two-by-two butt joint of four diodes BD1, and rectifies the AC input by the AC input unit 10 into dc, and inputs the dc to the overvoltage protection unit 30. Meanwhile, the overvoltage sampling point is arranged at the output end of the rectifying unit 20 to sample the real-time voltage value at the output end of the rectifying unit 20, so that the timeliness of real-time voltage sampling can be improved, and the VCC power supply unit 40 can be quickly turned off.

In this embodiment, the VCC unit is including starting module and voltage stabilizing module soon, it is used for quick start VCC unit to supply power for the load to open the module soon, voltage stabilizing module is used for supplying power for the load is stable, this scheme is through the input voltage who draws low VCC power supply unit 40's input, can realize turning off and recovering to VCC power supply unit 40 is holistic, not only can turn off and start module or voltage stabilizing module soon, no matter what output state VCC power supply unit 40 is in at present, all can realize quick turn-off, and stop the power supply, better protection power supply.

Referring to fig. 2, an input overvoltage protection system according to the present invention further includes a fuse having a first end connected to the AC input unit 10 and a second end connected to the rectifying unit 20, and the fuse is disconnected when an input current value is greater than a designated current value, so as to protect the entire input overvoltage protection system.

According to the input overvoltage protection system provided by the invention, the overvoltage protection unit 30 is used for sampling the real-time voltage value of the output end of the rectification unit 20 in real time, and when the real-time voltage value is larger than the turn-off voltage value, the overvoltage protection unit 30 is used for pulling down the input voltage of the input end of the VCC power supply unit 40, and the VCC power supply unit 40 is turned off to stop power supply, so that a power supply is protected under the condition of large power grid fluctuation; by sampling the real-time voltage value at the output end of the rectifying unit 20, the timeliness of real-time voltage sampling can be improved, so that the VCC power supply unit 40 can be quickly switched off; by pulling down the input voltage of the input terminal of the VCC power supply unit 40, the fast start module and the voltage stabilization module in the VCC unit can be pulled down simultaneously, and unified control is realized.

Referring to fig. 3, in an embodiment, the present invention further provides an input overvoltage protection method based on the input overvoltage protection system described in the above embodiment, which includes steps S110 to S130.

And S110, sampling the real-time voltage value at the output end of the rectifying unit in real time.

In this embodiment, the overvoltage protection unit is configured to sample the voltage value at the output end of the rectification unit, and control the VCC power supply unit to be turned on and off according to the voltage value at the output end of the rectification unit, and the overvoltage sampling point is set at the output end of the rectification unit to sample the real-time voltage value at the output end of the rectification unit, so that the timeliness of real-time voltage sampling can be improved, and the VCC power supply unit can be turned off quickly.

And S120, judging whether the real-time voltage value is larger than a preset turn-off voltage value or not.

And S130, if the real-time voltage value is greater than the turn-off voltage value, pulling down the input voltage of the input end of the VCC power supply unit through the overvoltage protection unit, and turning off the VCC power supply unit to stop power supply.

In this embodiment, in actual application, a turn-off voltage value for protecting the power supply device is preset according to the actual voltage that can be loaded by the power supply device, when the real-time voltage value exceeds the turn-off voltage value, the input voltage at the input terminal of the VCC power supply unit is pulled down to be close to 0V, the VCC power supply unit is turned off to stop supplying power to protect the power supply, and the voltage of the power supply device is prevented from exceeding the maximum voltage that can be loaded by the power supply device to damage the power supply device, so as to protect the power supply device under the condition of large power grid fluctuation.

Fig. 4 is a schematic flow chart of an input overvoltage protection method according to another embodiment of the present invention. As shown in fig. 4, the input overvoltage protection method of the present embodiment includes steps S210 to S250. Steps S210 to S230 are similar to steps S110 to S130 in the above embodiments, and are not described herein again. The steps S240 and S250 added in the present embodiment are explained in detail below.

S240, judging whether the real-time voltage value is smaller than a preset recovery voltage value.

And S250, if the real-time voltage value is smaller than the recovery voltage value, pulling up the input voltage of the input end of the VCC power supply unit through the overvoltage protection unit, and starting the VCC power supply unit to normally supply power.

In this embodiment, when the real-time voltage value is higher than the turn-off voltage value all the time, the VCC power supply unit keeps continuously in the turn-off state, when the real-time voltage falls back to be lower than or smaller than the recovery voltage value, the Mos transistor is turned off (not turned on), the input voltage at the input terminal of the VCC power supply unit is pulled up again, the power IC restarts to normally operate, the VCC power supply unit is started to normally supply power, and while the power supply equipment is protected, the power supply equipment can be ensured to be quickly restored to operate at a proper voltage.

The turn-off voltage value is greater than the recovery voltage value, and the difference value between the turn-off voltage value and the recovery voltage value is greater than the specified value, so that enough margin exists between the turn-off voltage value and the recovery voltage value, the power supply can be better protected, and the situation that when the difference value between the turn-off voltage value and the recovery voltage value is small, the VCC power supply unit is quickly turned off or recovered when the voltage fluctuates slightly, and the service life of the VCC power supply unit is influenced is avoided.

The technical contents of the present invention are further illustrated by the examples only for the convenience of the reader, but the embodiments of the present invention are not limited thereto, and any technical extension or re-creation based on the present invention is protected by the present invention. The protection scope of the invention is subject to the claims.